Researching the subject of Gas Holders & "Gasometers" as they are sometimes called, you soon realise that one gas holder looks pretty much like another - across the U.K certainly, the default design seems to follow that of the soon-to-be demolished Southall Gas Tower, (depicted here as a vector file illustration which you can purchase as a print) - a tall cylindrical structure painted a light blue - these usually date from the 1920' / 30's.
The other type often seen across London is a cylindrical open framework of cast iron, occasionally with ornamentation, a good example being the Gas Tower at The Oval - these usually date from the late Victorian era and many are already under preservation orders - the visible structure is built over the actual gas tank, which would have been submerged underground.
Similar Gas Towers exist across Europe and depending upon the era that they were constructed have varying levels of ornamentation, so that they appear to be "follies" at first glance - the castellated Southall Water Tower (also available here as a print) is a good example of Victorian Gothic attempts to make such utilitarian structures blend into a background of terraced housing - keeping apace with trends in architecture, structures from the Post-War period gradually became more "brutalist" and uncompromising in style, but retain a certain charm & impact due to their imposing scale.